Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Renal cell carcinoma (RCC) metastasis to the thyroid, albeit the most common carcinomatous metastasis to the thyroid, is rare, and tumor-to-tumor metastasis of RCC to PTC is even rarer. We present a case of a 65-year-old male with a history of RCC who presented with a thyroid nodule 7 years after left radical nephrectomy. Imaging showed the thyroid nodule predating the kidney tumor. Fine-needle aspiration biopsy was performed and showed 2 distinct cell populations, 1 of which was stained with RCC markers and another that was stained positively for thyroid markers. An interpretation of atypia of undetermined significance was rendered and molecular testing was indeterminate with ThyGeNEXT not detecting mutations and ThyraMIR positive for a level 2 microRNA pattern consistent with low risk for malignancy. The patient elected for active surveillance until follow-up thyroid ultrasound showed continued growth. At this point, a right hemithyroidectomy was performed. Pathology confirmed clear cell RCC metastasis to an infiltrative follicular variant papillary thyroid carcinoma. This case highlights the possibility of tumor-to-tumor metastasis in patients with a previous history of RCC even years after nephrectomy and in the absence of other metastatic lesions.
Patients with hypoparathyroidism can present with concurrent basal ganglia calcifications (BGCs). The exact pathogenesis is unknown, although it is thought to relate to calcium-phosphate deposition from chronic hypocalcemia and hyperphosphatemia. We present the case of a 65-year-old man with known idiopathic primary hypoparathyroidism and concurrent extensive BGC. Thirty years after diagnosis, he presented with focal seizures despite a decade of stable intracranial calcifications on imaging. Serum calcium, phosphate, 25-hydroxyvitamin D, and parathyroid hormone levels were well controlled during this period. He was commenced on lifelong levetiracetam with subsequent seizure remission. Given the scarcity of literature surrounding focal seizures and BGC, it is essential to raise awareness in this area.
We present a unique case of hypokalemic thyrotoxic periodic paralysis (TPP) in an adolescent girl in North America. TPP is a rare but dangerous complication seen in thyrotoxic patients characterized by hypokalemia and acute proximal symmetric lower-extremity weakness. It is an especially rare phenomenon in pediatrics, with roughly 20 case reports described in adolescents worldwide; the majority are male. Our patient is a 14-year-old Asian girl with biochemical hyperandrogenism and known Graves disease who presented with an acute episode of lower-extremity weakness after eating a carbohydrate-rich meal. Laboratory workup revealed hypokalemia, hypomagnesemia, an undetectable thyrotropin, and hyperthyroxinemia. Electrolyte derangements responded well to supplementation, and the muscle weakness resolved with electrolyte normalization. Following improvement in thyroid function, the patient underwent thyroidectomy for definitive management of Graves disease. As TPP is potentially exacerbated by higher androgen and insulin levels, we suspect that with increasing rates of obesity and polycystic ovary syndrome, the incidence of TPP among adolescents may increase. It is therefore critically important that there is awareness and recognition of this serious diagnosis among all health care providers.
We report a case of interstitial nephritis, likely secondary to oxalate nephropathy, due to the development of pancreatic exocrine dysfunction after commencement of pasireotide for acromegaly. Pasireotide is known to impair insulin secretion but can also impair pancreatic exocrine function, hypothezised to result from high-affinity binding of somatostatin receptors 1, 2, 3, and 5. This has been an advantage in postoperative tissue anastomoses after pancreatic surgery, but exocrine insufficiency has not been reported when used for the treatment of acromegaly. A 73-year-old woman, diagnosed with acromegaly, was unable to achieve biochemical control despite 2 surgical resections of an invasive mammosomatotroph pituitary tumor and treatment with cabergoline and maximal-dose lanreotide. The tumor expressed somatostatin receptor type 5 but not somatostatin receptor type 2, predicting good response from pasireotide, which was commenced at 40 mg every 4 weeks. IGF-1 rapidly normalized, but the patient presented with nausea, anorexia, and acute kidney injury. Renal biopsy revealed acute-on-chronic interstitial nephritis, with numerous oxalate crystals. Increased fecal fat globules were noted on fat stain (3+), supporting malabsorption as an etiology of secondary enteric hyperoxaluria. Renal function recovered to near baseline over months following pasireotide withdrawal and high-dose glucocorticoids.
Acromegaly is a rare pituitary condition stemming from hypersecretion of growth hormone (GH). Classic presentation involves enlarged hands, feet, and coarse facial features. However, late-onset cardiac manifestations develop in the absence of disease control. Of the various cardiac complications, heart failure is the rarest (3%-4% of cases). Here we present a case of acromegaly diagnosed after the patient exhibited symptoms of heart failure, with eventual placement of a left ventricular assist device (LVAD) as a bridge to orthotopic heart transplant. The 37-year-old patient originally presented with exercise intolerance and "heavy heartbeats" but was found to be in acute decompensated heart failure, with an ejection fraction (EF) of 15%. The acromegaly diagnosis was confirmed with labs, and he began treatment with lanreotide 120 mg weekly along with 0.5 mg cabergoline twice weekly. EF improved up to 30%. Soon after, he was lost to follow-up during the COVID-19 pandemic and returned with worsening EF. An LVAD was placed to support recovery while the patient awaited heart transplant. While LVADs are a common measure of cardiac support for ischemic cardiomyopathy, they can also be successful options in the setting of GH-driven cardiomegaly.
Diabetes is a risk factor for thyroid cancer development. Serum thyroglobulin (Tg) levels are useful as sensitive and specific tumor markers for monitoring radioiodine (RAI)-refractory thyroid cancer; however, the impact of glycemic control on serum Tg levels is poorly understood. Here, we present a case of a female patient with lung metastases of RAI-refractory thyroid cancer in whom glycemic control may have influenced the serum Tg levels. Despite receiving thyroid-stimulating hormone suppression therapy, her serum Tg levels remained elevated. Subsequently, she developed type 2 diabetes and was administered antidiabetic medications for 6 years. Throughout the course of diabetes management, her serum Tg levels fluctuated according to the level of glycemic control, showing a strong correlation with her hemoglobin A1c levels (r = 0.92, P < .01). Similar to the serum levels of other tumor markers, such as the carcinoembryonic antigen and carbohydrate antigen 19-9, the serum levels of Tg can be influenced by glycemic control. Therefore, serum Tg levels in patients with RAI-refractory thyroid cancer and diabetes should be monitored with attention to glycemic control.